Tire deflation switch



J. F. PROSPERO TIRE DEFLAT'ION SWITCH Filed Nov. 14, 1935 \NVENTOR h1.9%,

ATTORZJ Patented Oct. 13, 1936 UNITED STATES PATENT OFFICE TIREDEFLATION SWITCH Joseph F. Prospcro, Jersey City, N. J. ApplicationNovember- 14, 1935, Serial No. 49,665 3 Claims. (Cl. 200-58) Thisinvention relates to a safety device for vehicles having pneumatictires, the principal object of the invention being to provide anefficient device which I have termed herein a deflation switch by meansof which deflation of the tires will be automatically indicated to thedriver of the vehicle thereby warning him of the danger of a possibleblow out, and which device is simple in construction and economical tomanufacture and install.

Other objects and advantages of the invention will appear as thedescription proceeds.

In the drawing accompanying this specification.

Fig. 1 is aside view of an automobile wheel provided with a safetydeflation switch embodying the features of the present invention;

Fig. 2 is an edge view of the wheel showing the switch in normally openposition;

Fig. 3 is a view similar to Fig. 2, but showing the switch closed;

Fig. 4 is a longitudinal sectional view, on an enlarged scale, throughone member of the safety switch; and a Fig. 5 is an enlarged transversesectional view of the ball-bearing contact roller carried by the switchmember shown in Fig. 4.

As is well known to motorists, blow-outs quite frequently occur as theresult of slow leaks of air which, although not noticeable when thevehicle is at rest, become more active when traveling, at

which time there is of course no opportunity to observe the tires.Consequently, especially on a long journey, the occupants of a vehiclehaving pneumatic tires are exposed to the danger of a blow-out whichcould easily be avoided if the operator could in some way be warned ofthe deflation of the tire which usually precedes such a blow-out. It isthe object of this invention to provide a means for giving such awarning in good time to enable the operator to bring the vehicle to astop and take measures to stop the leak and thereby avoid the dangerincident to a blow-out.

Referring to the drawing, l designates an automobile wheel, which may beof the disk, wire or wood type, said wheel having the usual metal rim 2in which is mounted the pneumatic tire 3. The axle housing of thevehicle is indicated at 4, while 5 indicates the usual backing plate orflange carried at the opposite ends of said axle housing.

A complete safety signaling switch such as that about to be described isprovided for each wheel, and since they are all alike a description ofone will suffice.

The safety switch comprises a yoke member or bracket 6 made integralwith or rigidly secured to a cylindrical member or sleeve 1. A cap 8 isthreaded on the outer end of the sleeve and is provided in its end wallwith an opening through which passes a plunger rod 9 carrying at itsinner end a piston l0 adapted for reciprocation within the cylinder 1against the tension of a spring ll disposed in the cylinder, as clearlyshown in Fig. 4.

The assembly so far described and which forms one member of the safetyswitch, is secured on the backing plate 5 by means of bolts 12 passingthrough the legs of the yoke B and threaded into the backing plate, aninsulating member l3 being disposed between the backing plate and eachleg of the yoke, the bolts i2 being also insulated from the yoke byinsulating washers it. With the device thus mounted, the cylinder 1extends radially of the wheel and directly downward.

For cooperation with the switch member above described, a flexiblecopper ring or band i5 is vulcanized to the side of the tire casing orshoe in concentric relation to the tread of the tire, said band having aradial wire l6 extending into contact with a metal portion of the wheel.In case a wooden wheel is used the wire will extend down to a point ofthe wheel, preferably the hub, which contacts with the backing plate 5,as shown in the drawing to provide for groundirg. Near the outer end ofthe plunger rod 9 is mounted a ballbearing roller i1, said roller beingretained on the rod by a nut l8, and washer IS, the nut being threadedon the extreme end of the rod as shown in Fig. 4. The length of the rodis such that when projected out to its extreme position under thetension of the spring I the roller I! will lie in the same horizontalplane as the ring l5 secured on the tire casing.

The yoke 8 is sufllciently flexible to permit a slight adjustment of thecylinder I so as to increase or diminish the distance between the rollerl1 and the ring 15 on the tire. For accomplishing this adjustment, a.screw 20 is threaded through the cylinder at its point of juncture withthe yoke 6, the inner end of said screw bearing upon an insulatingwasher or block 2i secured on the backing plate 5. It will thus be seenthat by turning the screw 20 in one direction or the other the distancebetween the roller ii and ring I5 can readily be regulated.

The yoke 6 has secured thereto a lead wire 22 the opposite end of whichis intended to be connected to one pole of the car battery.

With a safety switch device as above described I tire is inflated to itsnormal capacity the contact 6 roller i1 is separated from the ringll,-as shown in Pig. 2. A suitable electrically operated indicator maybe mounted on the dash board of the vehicle and connected by separatecircuits to the devices of the individual wheels, so that should eitherof the tires develop a leak the resulting deformation or flattening oithe tire under the weight of the vehicle carrying the ring it intocontact with the roller IT, as shown in Fig. 3, the circuit through theindividual signalling device i'or that wheel will be closed so that theoperator is immediately warned of the threatened danger of a blow-out.

Having thus described my invention. what I claim is:

1. A deflation switch for pneumatic, tires, comprising a contact memberdisposed at one side of the tire and normally out of contact therewith,and an annular contact member carried by the tire at the side thereofadjacent to said first contact member and in po ition to be moved bydeflation oi the tire into contact with said first contact memberthereby to close an electric all circuit.

2. A deflation switch for pneumatic tires, comprising a contact memberdisposed at one side of the tire and normally out of contact therewith,an annular contact member carried by the tire at the side thereofadjacent to said flrst contact member and in position to be moved bydeflation of the tire into contact with said first contact memberthereby to close an electrical circult, and means Ior regulating thedistance between said contact members.

3. A deflation switch for pneumatic tires, comprising a contact rollerdisposed at one side of the tire and normally out of contact therewith,said roller being mounted for rotation in a direction at right angles tothe direction of travel or the tire, and a flexible annular contactmember carried by the tire at the side thereof adjacent to said contactroller in position to be flexed by deflation of the tire into contactwith said roller.

JOSEPH F. PROSPERO.

